在 MATLAB 中将图像划分为子图像时删除了部分图像

Question

我有一张336*104像素的图片，需要将其分成35*35的子图。但是 336 和 104 不能被 35 整除，因此当我分割它时图像的一部分被删除了。我得到了一个没有非 35*35 像素部分的重新组合图像。我无法调整它的大小，因为如果我这样做，图像会非常不同。这是我的代码：

% Size of the image
[H W] = size(im);

% Each sub image has 35*35 pixels
size_sub_image = 35;

% Size of each sub image
H_divided = H/size_sub_image;
W_divided = W/size_sub_image;

% Reminders allowing to take the images which are not divided
R_H = rem(H,size_sub_image);
R_W = rem(W,size_sub_image);

%Variable which is incremented and stand for each sub image
nbr_sub_images = 1;  

% Division of the image into sub images    
for i = 1:floor(H_divided)
    for j = 1:floor(W_divided)

        % R_H and R_W allow to create the sub images reminding, which have not
        %35*35 pixels. 
        %My idea was that when each i or j reach the max in the loop, the 
        %algorithm take the remindind images which have the size of R_H or R_W.
        % R_H = 21 (336 = 35*9+21) and R_W = 34 (104 = 35*2+34)

        if (i ~= floor(H_divided) && j ~= floor(W_divided))   

            nbr_sub_images = nbr_sub_images + 1;
            im_divided(:,:,nbr_sub_images) = im(size_sub_image*(i-1)+1:size_sub_image*i ,size_sub_image*(j-1)+1:size_sub_image*j );   

        end 

        if (i == floor(H_divided))

            nbr_sub_images = nbr_sub_images + 1;      
            im_divided(:,:,nbr_sub_images) = im(size_sub_image*(i-1)+1:size_sub_image*i ,size_sub_image*(j-1)+1:size_sub_image*j );

            nbr_sub_images = nbr_sub_images + 1;      
            im_divided(:,:,nbr_sub_images) = im(size_sub_image*i+1:size_sub_image*i + R_H,size_sub_image*(j-1)+1:size_sub_image*j);

        end

        if (j == floor(W_divided))

            nbr_sub_images = nbr_sub_images + 1;   
            im_divided(:,:,nbr_sub_images) = im(size_sub_image*(i-1)+1:size_sub_image*i ,size_sub_image*(j-1)+1:size_sub_image*j );

            nbr_sub_images = nbr_sub_images + 1;   
            im_divided(:,:,nbr_sub_images) = im(size_sub_image*(i-1)+1:size_sub_image*i,size_sub_image*j+1:size_sub_image*j + R_W);                 


        end

    end
end

当我执行它时，出现错误："Subscripted assignment dimension mismatch"，但我不明白为什么，因为当我删除 R_H 和 R_W 时，代码运行良好。

Answer 1

据我了解，您正试图将不同大小的子图像放入一个 3-D 数组中，这是行不通的。当您将二维图像添加到数组 im_divided 时，所有子图像的第一维和第二维必须相同（即 35x35）。有关详细信息，请参阅 MATLAB documentation.

有 2 种可能的解决方案：要么填充图像的边缘（用零或其他值）以便宽度和高度可以被 35 整除，要么使用元胞数组来存储子图像：

im_divided{nbr_sub_images} = im(rows, columns)

元胞数组能够存储不同大小的矩阵（或者实际上是各种不同的对象）。

在 MATLAB 中将图像划分为子图像时删除了部分图像

Part of an image removed when dividing an image into sub images in MATLAB

matlab

image-processing